1. Field of the Invention
The present invention relates in general to the field of battery cables for connecting a power source to a discharged battery with clamps. In particular, the present invention relates to battery cables having a light source for illuminating objects near the clamps.
2. Description of Related Art
The use of battery cables is well known in the prior art. As may be appreciated, these devices are potentially hazardous in the creation of sparks as the cables are connected or disconnected from the battery terminals. Also, it is important that each cable is connected to the proper battery terminal to eliminate short circuiting the power source. Numerous attempts have been made to develop jumper cables having indicating systems that effectively indicate proper battery connection. Many of these types of systems utilize LED's, or other visual indicators, which illuminate when the cables are properly connected. U.S. Pat. Nos. 4,938,712; 4,869,688; and 4,840,583; each disclose such a system. However, each of these systems requires a connection to the battery to be boosted before indication.
Often, jumper cables must be connected when it is dark or otherwise poorly lighted. Darkness makes it difficult to see the battery posts and ensure that the jumper cables' connectors are properly secured to the terminals. Furthermore, it is very difficult to identify the polarity of the battery terminals and jumper cable connections in the dark.
U.S. Pat. No. 5,367,243 discloses a retractable jumper cable attachment comprising a flashlight. A conventional flashlight is connected to both the positive and negative jumper cables. The connection is such that a switch enables the flashlight to be powered either by the battery to which the jumper cable is attached or to batteries contained in the flashlight in the traditional manner.
An improvement over the '243 design is disclosed in U.S. Pat. No. 6,254,426, in which an independent voltage source, such as a small battery, is carried within the grip portion of a battery clamp. This electrical power source is connected through a switch to a light source, which is mounted on the clamp. However, explosive gases may accumulate near a booster battery or the battery to be charged, and opening or closing an electrical circuit using a switch on the clamp can cause a spark that may ignite these gases. In addition, locating the electrical power source in the clamp may also lead to the creation of sparks if the batteries fit loosely within the clamp or otherwise break electrical contact during use. A similar design is shown in U.S. Pat. No. 5,420,767, though the design is directed toward clamps not used for electrical connections to a battery.
Although there have been significant developments over the years in the area of battery jumper cables, considerable shortcomings remain.